1. Field of the Invention
This invention is directed to an electrical switching apparatus and, more particularly, to a circuit interrupter, such as a circuit breaker, including an indicator for indication of circuit interrupter status information.
2. Background Information
Electrical switching apparatus include, for example, circuit switching devices and circuit interrupters such as circuit breakers, contactors, motor starters, motor controllers and other load controllers. Circuit breakers are generally old and well known in the art. Examples of circuit breakers are disclosed in U.S. Pat. Nos. 4,751,606; and 5,341,191. Such circuit breakers are used to protect electrical circuitry from damage due to an overcurrent condition, such as an overload condition or a relatively high level short circuit or fault condition.
Molded case circuit breakers include a pair of separable contacts per phase which may be operated either manually by way of a handle disposed on the outside of the case or automatically in response to an overcurrent condition. Typically, such circuit breakers include an operating mechanism, which is designed to rapidly open and close the separable contacts, and a trip mechanism, which senses overcurrent conditions in an automatic mode of operation. Upon sensing an overcurrent condition, the trip mechanism trips the operating mechanism to a trip state which moves the separable contacts to their open position.
Some trip mechanisms employ a microprocessor to detect various types of overcurrent trip conditions, such as, for example, a long delay trip, a short delay trip, an instantaneous trip, or a ground fault trip. Some of those trip mechanisms employ indicators, such as light emitting diodes (LEDs), to indicate the cause of the trip condition by lighting one of the LEDs.
Because circuit breakers are normally powered by current transformers on the load side of the separable contacts, some trip mechanisms employ battery-powered latches and displays to display the cause of the trip. In this manner, even if power is removed from the circuit interrupter, the user may determine the condition which caused the trip. With the loss of circuit interrupter power, it is not possible to recharge the battery or to permanently maintain the charge of the battery. Hence, there is room for improvement in battery-powered trip condition indicators for electrical switching apparatus.